The 53-year-old regular on the U.S. Champions Tour shot an even-par 72 in the final round at The Lakes to become the oldest Australian Open champion. Senor finished with a total of 4-under 284, keeping his composure while several other contenders struggled with the winds to drop down the field.
Fellow Australian Brendan Jones was second after a 71, while countryman Cameron Percy finished third after a 73, two strokes behind.
England's Justin Rose finished in a tie for fourth after a 76, three strokes behind Senior.
"Winning the PGA a couple of years ago up at Coolum was great, but I tell you what, nothing beats winning right here," Senior said.
Senior had 10 top-10 finishes on the Champions Tour this year, but no wins. That made the victory Sunday — with his son Mitch caddying — all the more special.
"It doesn't get any better than this," Senior said. "We've had three years on the Champions Tour where Mitch has caddied for me for the last two years, and we've lost three playoffs, so it feels unbelievable to win with him on the bag."
The previous oldest Australian Open champion was five-time British Open champion Peter Thomson at the age of 43 in 1972. Senior won the Australian Open for the first time as a 30-year-old in 1989.
On Sunday morning, gusts of up to 50 mph during a southerly wind change caused one television tower to topple, balls to move on the fairways and greens and sand to be blown from bunkers and into the galleries and fairways.
The gusty winds remained after play resumed, and third-round leader John Senden shot 82, second-round leader Marcus Fraser had an 81 and Adam Scott carded 76 to finish well of the pace.
Joining them, defending champion Greg Chalmers and Geoff Ogilvy each shot 77s. But 1984 champion Tom Watson was lucky to have started early Sunday morning, shooting a 69 before the storm hit to climb into a tie for 28th.
Tournament chief Trevor Herden said officials had no alternative but to suspend play when the fierce winds hit the course just before midday in Sydney.
"Obviously there's nothing we can do to protect anybody other than to get them out of danger," Herden said. "We have an obligation to the public and the players and then there's the golf course, which at that point became unplayable."Suggest a correction